Oil field operators demand access to a great quantity of information regarding the parameters and conditions encountered downhole. A wide variety of logging tools have been and are being developed to collect information relating to such parameters as position and orientation of the bottomhole assembly, environmental conditions in the borehole, and characteristics of the borehole itself as well as the formations being penetrated by the borehole.
A number of these logging tools require a downhole source of illumination, e.g., borehole wall imaging tools, spectral analysis tools, and some types of fluid flow analysis tools. As one particular example, operators often wish to perform downhole formation testing before finalizing a completion and production strategy. Fluid sampling tools enable operators to draw fluid samples directly from the borehole wall and measure contamination levels, compositions, and phases, usually based on the optical properties of the materials drawn into the sample chamber. The light source for such a downhole tool is subject to a number of challenges and restrictions. Often, the energy consumption of the light source is limited, as is the volume which can be set aside for the source. In many cases, the existing light sources are unable to satisfy the combined requirements for a rugged, small volume, broad-spectrum source that includes sufficient intensity for performing spectral analysis in the near-infrared (“NIR”).
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the plain-language scope of the claims.